code: def test_multiplexed_lru_policy(serve_instance):
      """Test multiplexed function LRU policy"""
  
      @serve.deployment
      class Model:
          @serve.multiplexed(max_num_models_per_replica=2)
          async def get_model(self, tag):
              return tag
  
          async def __call__(self, request):
              tag = serve.get_multiplexed_model_id()
              await self.get_model(tag)
              # return pid to check if the same model is used
              return os.getpid()
  
      handle = serve.run(Model.bind())
      headers = {SERVE_MULTIPLEXED_MODEL_ID: "1"}
      requests.get("http://localhost:8000", headers=headers)
      headers = {SERVE_MULTIPLEXED_MODEL_ID: "2"}
      requests.get("http://localhost:8000", headers=headers)
      # Make sure model2 will be evicted
      headers = {SERVE_MULTIPLEXED_MODEL_ID: "1"}
      requests.get("http://localhost:8000", headers=headers)
      headers = {SERVE_MULTIPLEXED_MODEL_ID: "3"}
      requests.get("http://localhost:8000", headers=headers)
  
      wait_for_condition(
          (
              lambda: check_model_id_in_replicas(handle, "1")
              and check_model_id_in_replicas(handle, "3")
          )
      )
  
imports: import asyncio
  import os
  from typing import List
  import pytest
  import requests
  import ray
  from ray import serve
  from ray._private.test_utils import SignalActor, wait_for_condition
  from ray._private.utils import get_or_create_event_loop
  from ray.serve._private.constants import SERVE_MULTIPLEXED_MODEL_ID
  from ray.serve.context import _get_internal_replica_context
  from ray.serve.handle import RayServeHandle
  from ray.serve.multiplex import _ModelMultiplexWrapper
label_desc: Use image node_id 6 for calling a global function with example usage: test_multiplexed_lru_policy(serve_instance) and returns: tag, os